1. Field of the Invention
The present invention relates to an end machining apparatus and holding fixtures for optical connectors.
2. Description of the Related Art
In connecting optical fibers to one another, optical connectors are attached individually to the respective ends of the optical fibers, and the respective end faces of the connectors are butted against one another.
The following is a description of a conventional method of attaching an optical connector to the ends of the optical fibers, e.g., on an end of a tapefiber which includes a plurality of optical fibers.
First, the end portion of the tapefiber with its optical fibers exposed is inserted into a hollow in the optical connector, which is formed having a plurality of fiber holes for the optical fibers as well the hollow therein, and the exposed optical fibers are inserted individually into the fiber holes. Then, an adhesive agent is filled into the hollow of the optical connector, and is set by heating. Thereupon, each optical fiber slightly projects from the end face of the optical connector, and the adhesive agent is swollen on the end face of the connector as it is set.
After the adhesive agent swollen on the end face of the optical connector and the optical fibers are ground by means of a grinding material, the optical connector is subjected to end machining such that its end face is ground and polished into a specular surface.
In the conventional optical connector end machining, end grinding of the optical connector is started under grinding conditions (load of pressure, grinding speed, abrasive grain coarseness, etc.) used in shaving off the adhesive agent swollen on the end face. Accordingly, the grinding conditions are so heavy that the end face of the optical connector is liable to be marred. Moreover, the depth of grinding varies considerably, depending on the quantity of the adhesive agent, thus exerting a bad influence upon the accuracy of connection of the optical connectors.
If the end faces of the optical fibers are scratched during this grinding process, in particular, it is very hard to mend the scratches by finish polishing afterward. The scratches on the optical fiber end faces must be eliminated because they may increase the connection loss or reflection of transmitted signal light.
The scratches on the optical connector end faces can be eliminated by lightening the grinding conditions for the removal of the adhesive agent which mainly causes the scratches. If the grinding conditions are softened, however, the grinding time is lengthened, thus entailing an increase of the cost of attaching the optical connector to the optical fiber ends.
In another method of elimination, the position of the end face of the optical connector is detected so that the grinding operation for the removal of the adhesive agent can be stopped when the distance between the grinding material and the end face is zero or when the adhesive agent barely exists between the grinding material and the end face.
According to this method, however, the delivery rate of the grinding material must be controlled precisely, so that the end machining apparatus inevitably entails high cost.
According to conventional machining apparatuses for machining the connector end face, moreover, the adhesive agent swollen on the end face of the optical connector and the optical fibers are ground by means of the grinding material of one machining apparatus, while the end face is polished into a specular surface by using another machining apparatus. Thus, the productivity of the optical connectors is too low for the automation of the end machining.
Furthermore, the optical connector end machining involves a problem that the end machining accuracy is lowered unless the optical connector is held securely.